The optical fiber drawing is a procedure of completing fiber drawing and forming after melting an optical fiber preformed rod at a high temperature through a fiber drawing furnace. The existing optical fiber drawing furnace heating apparatus is mainly formed of a furnace casing, an exothermic sleeve mounted in the furnace cavity, a heat-insulation layer mounted around the exothermic sleeve, and an induction coil. The existing optical fiber drawing furnace is mainly suitable for machining an optical fiber preformed rod with the diameter being 60 to 80 mm. With developments of optical fiber technologies, the field of the optical fiber drawing begins to seek for the fiber drawing of an optical fiber preformed rod with the diameter being greater than 100 mm, so as to reduce the cost of the optical fiber drawing to a large extent, and improve the manufacturing efficiency of the fiber drawing devices. Conventionally, it is difficult for the existing optical fiber drawing furnaces, due to being subject to restriction of many factors such as structures of main components and the exothermic amount gradient distribution, to adapt to fiber drawing and machining of a large-diameter optical fiber preformed rod. Thus, researches and developments of a large-diameter preformed rod fiber drawing furnace are very pivotal.